<template>
  <div class="app-container">
    课程列表
    <!--查询表单-->
    <el-form
      :inline="true"
      class="demo-form-inline">
      <!-- 所属分类：级联下拉列表 -->
      <!-- 一级分类 -->
      <el-form-item label="课程类别">
        <el-select
          v-model="searchObj.subjectParentId"
          placeholder="请选择"
          @change="subjectLevelOneChanged">
          <el-option
            v-for="subject in subjectNestedList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
        <!-- 二级分类 -->
        <el-select v-model="searchObj.subjectId" placeholder="请选择">
          <el-option
            v-for="subject in subSubjectList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
      </el-form-item>
      <!-- 标题 -->
      <el-form-item>
        <el-input v-model="searchObj.title" placeholder="课程标题"/>
      </el-form-item>
      <!-- 讲师 -->
      <el-form-item>
        <el-select
          v-model="searchObj.teacherId"
          placeholder="请选择讲师">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"/>
        </el-select>
      </el-form-item>
      <el-button type="primary"
                 icon="el-icon-search"
                 @click="fetchData()">查 询</el-button>
      <el-button type="default" @click="resetData()">清空</el-button>
    </el-form>
    <!-- 表格 -->
    <el-table
      v-loading="listLoading"
      :data="list"
      element-loading-text="数据加载中"
      border  fit  highlight-current-row
      row-class-name="myClassList">
      <el-table-column
        label="序号"
        width="70"
        align="center">
        <template slot-scope="scope">{{ (page - 1) * limit + scope.$index + 1 }}    </template>
      </el-table-column>
      <el-table-column label="课程信息" width="470" align="center">
        <template slot-scope="scope">
          <div class="info">
            <div class="pic">
              <img :src="scope.row.cover" alt="scope.row.title" width="150px">
            </div>
            <div class="title">
              <a href="">{{ scope.row.title }}</a> 课时<p>{{ scope.row.lessonNum }} </p>
            </div>
          </div>
        </template>
      </el-table-column>
      <el-table-column label="创建时间" align="center">
        <template slot-scope="scope">      {{ scope.row.gmtCreate.substr(0, 10) }}    </template>
      </el-table-column>
      <el-table-column label="发布时间" align="center">
        <template slot-scope="scope">
          {{ scope.row.gmtModified.substr(0, 10) }}
        </template>
      </el-table-column>
      <el-table-column label="价格" width="100" align="center" >
        <template slot-scope="scope">
          {{ Number(scope.row.price) === 0 ? '免费' :      '¥' + scope.row.price.toFixed(2) }}    </template>
      </el-table-column>
      <el-table-column prop="buyCount" label="付费学员" width="100" align="center" >
        <template slot-scope="scope">      {{ scope.row.buyCount }}人    </template>
      </el-table-column>
      <el-table-column label="操作" width="150" align="center">
        <template slot-scope="scope">
          <router-link :to="'/course/info/'+scope.row.id">
            <el-button type="text" size="mini" icon="el-icon-edit">编辑课程信息</el-button>
          </router-link>
          <router-link :to="'/course/chapter/'+scope.row.id">
            <el-button type="text" size="mini" icon="el-icon-edit">编辑课程大纲</el-button>
          </router-link>
          <el-button type="text" size="mini" icon="el-icon-delete" @click="deleteCourese(scope.row.id)">删除</el-button>
        </template>
      </el-table-column> </el-table>
    <!-- 分页 -->
    <el-pagination
      :current-page="page"
      :page-size="limit"
      :total="total"
      style="padding: 30px 0; text-align: center;"
      layout="total, prev, pager, next, jumper"
      @current-change="fetchData" />
  </div>
</template>
<script>
  //引入调用teacher.js文件
  import course from '@/api/course'
  import teacher from '@/api/teacher'
  import subject from '@/api/subject'

  export default {
    data() { //定义变量和初始值
      return {
        listLoading: true, // 是否显示loading信息
        list: null, // 数据列表
        total: 0, // 总记录数
        page: 1, // 页码
        limit: 10, // 每页记录数
        searchObj: {
          subjectParentId: '',
          subjectId: '',
          title: '',
          teacherId: ''
        }, // 查询条件
        teacherList: [], // 讲师列表
        subjectNestedList: [], // 一级分类列表
        subSubjectList: [] // 二级分类列表,
      }
    },
    created() { //页面渲染之前执行，一般调用methods定义的方法
      this.fetchData()
      // 初始化分类列表
      this.initSubjectList()
      // 获取讲师列表
      this.initTeacherList()
    },
    methods:{
      fetchData(page = 1) {
        // 调用api层获取数据库中的数据
        console.log('加载列表')
        // 当点击分页组件的切换按钮的时候，会传输一个当前页码的参数page
        // 解决分页无效问题
        this.page = page
        this.listLoading = true
        course.getPageList(this.page, this.limit, this.searchObj)
          .then(response => {
            // debugger 设置断点调试
            if (response.success === true) {
              this.list = response.data.row
              this.total = response.data.total
            }
            this.listLoading = false
          })
      },
      initTeacherList() {
        teacher.getListTeacher()
          .then(response => {
            this.teacherList = response.data.teachers;
          })
      },
      initSubjectList() {
        subject.getSubjectList()
          .then(response => {
            this.subjectNestedList = response.data.list
          })
      },
      subjectLevelOneChanged(value) {
        for (let i = 0; i < this.subjectNestedList.length; i++) {
          if (this.subjectNestedList[i].id === value) {
            this.subSubjectList = this.subjectNestedList[i].children
            this.searchObj.subjectId = ''
          }
        }
        },
      resetData() {
        this.searchObj = {}
        this.subSubjectList = [] // 二级分类列表
        this.fetchData()
      },
      //删除课程
      deleteCourese(courseId){
        this.$confirm('此操作将永久删除该课程，以及该课程下的章节和视频，是否继续?', '提 示', {
          confirmButtonText: '确定',
          cancelButtonText: '取消',
          type: 'warning'
        }).then(() => {
          return course.delete(courseId)
        }).then(() => {
          this.fetchData()
          this.$message({
            type: 'success',
            message: '删除成功!'
          })
        }).catch((response) => { // 失败
          if (response === 'cancel') {
            this.$message({
              type: 'info',
              message: '已取消删除'
            })
          }
        })
      }
    }
  }
</script>
